Pneumatic stop detector



sept- 3 A. E. HUDD 1,972,301

PNEUMATIC STOP DETECTOR Filed Feb. 21, 192'! 2 Sheets-Sheet 1 InuEnZuP- Hlfred Ern'EEZHudd.

Egg-I PNEUMATIC STOP DETECTOR Filegi Feb. 21, 192'! 2 Sheets-Sheet 2 Fig:

Imrsnlur- Patented Sept. 4, 1934 UNITED STATES P TEN OFFICE mesne assignments,

to Associated Electric Laboratories, Inc., Chicago, Ill.,a corporationof Delaware Application February 21, 1927, SerialNo. 170,048

1'7 Claims.

The present invention, relates in general to stop detectors, but is particularly concerned with the construction and. design of a pneumatic stop detector.

'5 The object of the invention is to provide pneumatic equipment for controlling electrical devices, but which can only be effectively operated to procure the intended function when associated apparatus is at a standstill.

Stop detecting equipment of the foregoing character has considerable utility in various diversified fields. For instance, in train control systems and in the operation of signalling systems in mines. In train control systems it is common practice to require a train to be brought to a standstill following an automatic brakeapplication before the engineman is permitted torelease the brakes. In order to guard against the engineinans failing to obey orders by releasing the brakes before the train has actually stopped, it has been the custom to provide a releasing lever or key at a position necessitating the engineman to get down off the train. This practice is objectionable however, owing to the danger to the engineman and to passengers should the engineman be required to get off his locomotive to release the brakes after the train has been stopped in a poorly ventilated tunnel or on a tressel-bridge or the like.

In mines various signals are often transmitted and controlling influences exercised having a direct vbearing on the movement of the elevator, it being important to avoid the change of a signal while the elevator is moving. The present device will serve very nicely in a situation of this kind.

Referring now to the drawings, comprising Figs. 1 and 2 which, when taken togethenclearly illustrate the invention.

In considering the invention more in detail, Fig. 1 should be placed above Fig.2. Fig. 1 shows a pneumatic switching device 13 containing two pairs of contacts, although any number or combination may be added as required. This device is of well known construction and is adapted to be pneumatically operated in a manner which will. be hereinafter described. I

The part C is a standard type of air valve and is used for the purpose of obtaining a manual control of the device from a location which proves most desirable. If it isbeing used as a part of a train control system it will be located in the cab of thelocomotive.

Connected with the foregoing devices and 55 shown in Fig. 2, is a special type of spherical and its threaded end is extended through a cenis assembled in place under tension.

9 connecting the inside of the piston 4 with at- -by nuts 26 and 26'.

valve, which is mounted preferably over one of the driving wheels of the locomotive, and with its part 5 pointed directly toward the track surface of the wheel, in line with its axis.

Since the air valve C and pneumatic switch B 6 are both of well known construction a description .Thisplug is provided with apertures .13 and 13 for admitting air into the piston. A leather cup washer 14 is also secured to this plug by brass washer 14' held in place by nut 15. The washers 14 and 14' both have apertures similar to apertures 13 and 13 and are held in register therewith by pins 16 and 16'. A bolt 1'7 carrying a helical spring 18 is placed within the piston 4 tral aperture in plug 12 and extends beyond the pend of the piston. A washer 19 having apertures like those of plug 12 is held onthe end of the cylinder 10 by a cap 23 to which compressed air is supplied via pipe 2. A spacing sleeve 20 onbolt ;17 keeps the piston 4 a fixed distance from the holding washer 19 to which the bolt is secured. by nut 21 and locking nut 22. The spring 18 The other end of the piston, 4 is internally threaded to receive a valve sea't'll. This valve seat is normally closed by a spherical valve element 5, which has a plurality of. fluted openings v mosphere whenever the element 5 is rotated out of alignment with the piston, it being normally held in proper alignment therewithby a slightly compressed conical spring 8. 1

The valve A is held in position by a bracket 25 .95 surrounding the cylinder 10 and held in place b The operation of this valve under control of the air valve C and its influence on the operation of the pneumatic switch B will now be explained.

When the lever 1,0f valve C is depressed, air pressure from a main reservoir connected with opening 30, in the case of use with a train control system, is admitted to the pipe 2, which is in communication with the fixed cylinder 10 of the valve A and with the pneumatic switch B. As a result of the opening of the valve C air pressure is applied to the piston 3 of the pneumatic switch B and to the piston 4 of the spherical valve A. The pressure, however, is not at this time suflithe moving wheel.

cient to operate piston 3 on account of the fact that the restoring spring 18 of the piston 4 is adjusted to permit its operation by relatively low pressure as compared to that required to operate B. The piston 4 therefore immediately begins to move towards the wheel W.

As previously explained, the element 5 of the valve A is only held on its seat by conical spring 8, which also acts as a centering device to keep the element in position. The strength of the spring is so adjusted that it will hold the valve on its seat with sufiicient pressure to enable say from 10 to 20 lbs. of air pressure to build up in the cylinder 10. This low pressure is sufiicient to force the piston 4 outward in order that the valve element 5 carried by the piston 4 may engage with the locomotive wheel. It will be seen therefore that unless the valve element 5 is held in a central position, which will occur only when the wheel is stationary, it will be impossible for the air pressure in the pneumatic switch to raise sufficiently to enable its contacts to be operated. As soon as element 5 is pressed against the stationary wheel of the locomotive the forward movement of piston 4 ceases and the air valve is held firmly closed irrespective of the'air pressure. As soon as the valve is held closed in this manner the pressure within'the cylinder of the valve A and of course in the pipe 2, and also in the cylinder of the pneumatic switch B will rapidly rise. The area'of piston 3, the weight of 'the piston itself and the length of the spring 6 that it requires the 'full main the piston. When this is so proportioned attempts to operate the device he will find it impossible to close the pneumatic switch B for the reason that immediately when the'tip of element I 51 of the spherical valve comes into contact with the wheel W it will be deflected on account of the piston 4 and because of When this occurs air leaks through the escape slots 9 and will prevent any increase in the pressure being applied to the pistons 3 and 4 and will therefore prevent the necessary increase of pressure on p1ston 3 to enable the pressure behind it to operate.

It will be noted that devices B and A are normally connected with atmosphere via openings "28 of valve C. Therefore, uponthe release of 'lever l, the air in pipe 2 is vented to atmosphere through these openings and devices A'and B are restored to their normal position by their springs 18, 8 and 6, respectively.

What is claimed is:

1. In a'pneumatic valve, an air release member, a seat for said member, pneumatic means for moving said member into engagement with an object, said pneumatic means being efiective if theobject encounteredis stationary tohold said member tightly upon its seat in the same relation thereto as before encountering the object and effective if the object encountered is moving 'to deflect said member on its seat to connect the pneumatic means with atmosphere.

2. In combination with a movable member, a manually operable device, other devices controlled thereby, and means associated with one of said devices cooperative with the movable member in a manner dependent on whether the member is moving or at a standstill to determine whether another of said devices will or will not be operated.

movable element to cause or prevent the escape of air through said valve depending on whether the movable element is moving or stationary.

5. In a pneumatic valve, a pneumatically operable piston, an air release member carried by said piston, and movable means within the range of operation of said air release member efiective, when encountered by said member, to operate it or not dependent on whether said movable .means is or is not moving.

compressed spring having one end resting against.

a portion of said seat and having its other end secured to said extension, and a second extension on said valve member for rotating the same.

7. In combination a movable member, a sec ond movable member, other members controlled thereby, and means associated with one of said other members cooperable with the first member in a manner dependent on whether said first member is or is not moving to determine whether another of said members will be affected by the movement of the second member.

8. A resetting device for automatic train control comprising vehicle-carried means adapted to contact with a relatively movable part to be moved therewith, and resetting-effecting means operable when said means contacts with said part without being moved therewith.

.9. A resetting device for automatic train control comprising vehicle-carried means including a member mounted for movement to and from a relatively movable part and adapted to be moved in another direction by said part when the vehicle is in motion, said member having a portion to contact with said part, means for pro- 'ecting said member to bring said contact with said part, and resetting-efiecting means operable when said member is projected without said member being moved by said part.

10. A resetting device for automatic train control comprising vehicle-carried means including a member mounted for swinging movement and for movement to and from a relatively movable part, means for projecting said member, said member having a portion to contact with said part when said member is projected so as to swing said member when the vehicle is in motion, and resetting-effecting means controlled by the aforesaid means to be operable when said member is projected without being swung by said part.

11. A resetting device for automatic train control comprising a member mounted for swinging motion, a member carried thereby to be projected and retracted and having a yieldable portion to contact with a relatively movable part when the vehicle is in motion, means for projecting the second named member to bring said portion into contact with said part, and resetting-effecting means operable when the second named member is projected and rendered inoperable portion into.

when the first named member is swung by the movement of said portion with said part.

12. A resetting device for automatic train control comprising vehicle-carried means adapted to be moved by motion of the vehicle, and resetting-efiecting means capable of being operated when said means is not so moved.

13. A resetting device for automatic train control comprising vehicle-carried means controlled manually to be moved by the motion of the vehicle, and resetting-efiecting means controlled simultaneously with the first named means and arranged to be operated when the first named means is not moved by the motion of the vehicle.

14. A resetting device comprising a slidable member, a trip member pivoted thereto and adapted to contact with a relatively movable part, and resetting efiecting means operable when said slidable member is moved to bring said trip member against said part with said part relatively stationary.

15. A resetting device comprising a slidable member, a member in which said member is slidable, a trip member pivoted to said slidable member and adapted to be drawn into the secondnamed member and to be projected into contact with a relatively movable part for tripping said trip member, and resetting effecting means operable whensaid slidable member is moved to bring said trip member against said part when said part is relatively stationary.

16. A resetting device comprising a slidable member, a trip member pivoted thereto and adapted to contact with a relatively movable part, means between said members for yieldingly holding the trip member in alinement with said slidable member, and resetting effecting means operable when said slidable member is moved to bring said trip member into contact with said part without being swung from alinement with said slidable member.

17. A resetting device comprising a slidable member, a trip member pivoted thereto and adapted to contact with a relatively movable part, and resetting effecting means operable when said slidable member is moved to bring said trip member against said part with said trip member remaining in a predetermined position with reference to the slidable member.

ALFRED E. HUDD. 

